1. Field of the Invention
The present invention relates generally to microelectronic fabrications. More particularly, the present invention relates to bond pad corrosion inhibited microelectronic fabrications.
2. Description of the Related Art
Microelectronic fabrications are formed microelectronic substrates over which are formed patterned microelectronic conductor layers which are separated by microelectronic dielectric layers.
Within the general art of microelectronic fabrication, there exist purely electronic microelectronic fabrications whose operation is based solely upon electrical signal storage and processing characteristics of purely electronic microelectronic devices and microelectronic circuits formed upon a microelectronic substrate. Examples of such purely electronic microelectronic fabrications typically include, but are not limited to, semiconductor integrated circuit microelectronic fabrications and ceramic substrate microelectronic fabrications. Similarly, there also exist within the general art of microelectronic fabrication microelectronic fabrications whose operation is based upon a codependent transduction, storage and/or processing of optical and electrical signals while employing optoelectronic microelectronic devices formed upon a microelectronic substrate. Examples of such optoelectronic microelectronic fabrications typically include, but are not limited to: (1) solar cell optoelectronic microelectronic fabrications; and (2) image array optoelectronic microelectronic fabrications such as but not limited to: (a) sensor image array optoelectronic microelectronic fabrications; and (b) display image array optoelectronic microelectronic fabrications.
Common to all microelectronic fabrications, whether purely electronic microelectronic fabrications or optoelectronic microelectronic fabrications, is the use of bond pads as a means for connecting and interconnecting the microelectronic fabrications into useful microelectronic products.
While the use of bond pads for connecting and interconnecting microelectronic fabrications, including but not limited to purely electronic microelectronic fabrications and optoelectronic microelectronic fabrications, into useful microelectronic products is quite common in the art of microelectronic fabrication, the use of bond pads when connecting and interconnecting microelectronic fabrications, including but not limited to purely electronic microelectronic fabrications and optoelectronic microelectronic fabrications, into useful microelectronic products is not entirely without problems in the art of microelectronic fabrication.
In that regard, incident to exposure to various microelectronic fabrication processes there is often corroded, eroded, stained or otherwise degraded bond pads which are employed within microelectronic fabrications. Although various mechanisms may provide such corroded, eroded, stained or otherwise degraded bond pads, within the context of the present invention the terminology xe2x80x9ccorrosionxe2x80x9d or xe2x80x9ccorrodedxe2x80x9d is intended to include physical and/or electrical performance degradation of a bond pad employed within a microelectronic fabrication, irrespective of the actual mechanism through which such physical or electrical performance degradation actually occurs. Use of corroded bond pads is undesirable in the art of microelectronic fabrication since it is often difficult to form fully functional or reliable electrical connections within a microelectronic fabrication when employing a corroded bond pad.
It is thus towards the goal of providing within the art of microelectronic fabrication methods and materials for forming within microelectronic fabrications bond pads with attenuated corrosion that the present invention is most generally directed. More particularly, it is also towards the goal of providing within the art of optoelectronic microelectronic fabrication methods and materials for forming within optoelectronic microelectronic fabrication bond pads with attenuated corrosion that the present invention is more specifically directed.
Various methods and materials have been disclosed in the art of microelectronic fabrication for forming within microelectronic fabrications bond pads with desirable properties.
Included among the methods and materials, but not limited among the methods and materials, are methods and materials disclosed within: (1) Chalco et al., in U.S. Pat. No. 6,130,479 (a method for forming within a solder joint connected to a bond pad a comparatively thin intermetallic layer, by forming over the bond pad a nickel layer having formed thereupon a noble metal (preferably gold) layer and thermally annealing the same to form a nickel-noble metal alloy layer, prior to forming and thermally annealing over the nickel-noble metal alloy layer a tin containing solder layer); and (2) Lan et al., in U.S. Pat. No. 6,214,717 (a method for inhibiting bond pad staining and enhancing bond pad bondability, particularly within an optoelectronic microelectronic fabrication, by treating an aluminum-silicon-copper alloy bond pad with a fluorine containing plasma prior to bonding thereto a bond wire).
Desirable in the art of microelectronic fabrication are additional methods and materials which may be employed for attenuating within a microelectronic fabrication corrosion of a bond pad formed within the microelectronic fabrication. More particularly desirable in the art of optoelectronic microelectronic fabrication are additional methods and materials which may be employed for attenuating within an optoelectronic microelectronic fabrication corrosion of a bond pad formed within the optoelectronic microelectronic fabrication.
It is towards the foregoing objects that the present invention is both generally and more specifically directed.
A first object of the invention is to provide a method for attenuating within a microelectronic fabrication corrosion of a bond pad formed within the microelectronic fabrication.
A second object of the present invention is to provide a method in accord with the first object of the present invention, where the microelectronic fabrication is an optoelectronic microelectronic fabrication.
A third object of the present invention is to provide a method in accord with the first object of the present invention and the second object of the present invention, wherein the method is readily commercially implemented.
In accord with the objects of the present invention, there is provided by the present invention a microelectronic fabrication and a method for fabricating the microelectronic fabrication.
To practice the method of the present invention, there is first provided a substrate. There is then formed over the substrate a bond pad formed of a conductor material selected from the group consisting of aluminum and aluminum alloy conductor materials. There is then formed upon the bond pad a conductor passivation layer formed of a noble metal conductor material. Preferably the noble metal conductor material is selected from the group consisting of gold and gold alloy conductor materials.
The method for fabricating the microelectronic fabrication in accord with the present invention contemplates a microelectronic fabrication fabricated in accord with the method for fabricating the microelectronic fabrication in accord with the present invention.
Similarly, both the method for fabricating the microelectronic fabrication in accord with the present invention and the microelectronic fabrication fabricated in accord with the method for fabricating the microelectronic fabrication in accord with the present invention provide particular value within the context of fabricating image array optoelectronic microelectronic fabrications, and in particular color filter sensor image array optoelectronic microelectronic fabrications.
The present invention provides a method for attenuating within a microelectronic fabrication corrosion of a bond pad formed within the microelectronic fabrication, where the microelectronic fabrication may be, and preferably is, an optoelectronic microelectronic fabrication.
The present invention realizes the foregoing object by employing when forming the microelectronic fabrication, and formed upon a bond pad formed of an aluminum or aluminum alloy conductor material formed over a substrate employed within the microelectronic fabrication, a conductor passivation layer formed of a noble metal conductor material, preferably selected from the group consisting of gold and gold alloy conductor materials.
The method of the present invention is readily commercially implemented.
The present invention employs methods and materials as are otherwise generally conventional in the art of microelectronic fabrication, but employed within the context of specific materials selections and specific process limitations to provide the present invention. Since it is thus at least in part a series of materials selections and process limitations which provides at least in part the present invention, rather than the existence of methods and materials which provides the present invention, the method of the present invention is readily commercially implemented.